Martin,
Our Sony has just developed the same fault worked fine yesterday but after switching to stby last night it was stuck on updating when we checked almost 24 hrs later. Managed to get out of that by powering off for a few minutes but now EPG is doing the same as your's and no channels are output. Question where do you live as I found something on the web about 4G upgrades in our area (west sussex) may disrupt freeview receivers!
peter, July 2013